Analysis of samples of material by spectroscopic methods, eg near infrared spectroscopy, is a well documented procedure, using the spectroscopic signature of a material to determine its physical and chemical properties. This methodology is typically used to quantify the quality and characteristics of materials delivered to bulk receiving centres by taking a small sample of the material (which is supposed to statistically represent the whole mass) and subjecting the sample to laboratory spectroscopic analysis. Using well understood techniques and commercially available spectrometers and computer statistical software, database and chemometric calibrations are applied to determine the parameters of the sample. This methodology is applied in such industries as grain handling at silos, wine grape receiving at wineries and environmental disposal centres. Those delivering products may be paid for the quality/characteristics of the delivered material based on this analysis and the analysis may be used to group or store the received material.
The deficiencies in current systems are the difficulty in taking representative samples, the difficulty in removing and processing the samples, the laboratory handling of the samples and the time taken to produce a result. This is especially important when subsequent handling and movement of the delivered product is dependent on the result of the analysis, often causing a delay in production processes.
By way of example, when a grower delivers a truckload of wine grapes to a winery receiving centre, samples of the load are usually taken with a mechanical device which plunges into the load and removes a quantity of grapes from up to four different places by a complex mechanical shutter arrangement. The extracted sample is then disgorged, examined by hand and a subsample of grapes removed for “colour” analysis by near infrared spectroscopy in the laboratory. Then a juice sample (from the natural pressing of the weight of the grapes in the truck) is removed from the bottom layer of the truck by a suction process and the juice subjected to further laboratory handling to produce values for brix and other parameters by near infrared spectroscopy. The results of these processes are then used by the winemaker to determine grower payment and how the grape load will be handled for crushing (ie used for premium wine, specialty wine or for lower value bulk wine). These decisions must be made “on the fly” and the driver directed to the appropriate crushing unit with as little delay as possible.
Likewise, when a bulk load of grain is delivered to a silo, samples of the load are removed by a vacuum lance and the aggregate taken into the laboratory. A small subsample is then placed in a cuvette, petri dish or sample holder and placed into a spectrometer for analysis of parameters such as protein and moisture. The result of this analysis is used for grower payment, type determination, quality designation, holding location and subsequent storage.
These current methods are far slower than industry would like and there are questions over the statistical validity of the small samples actually tested.
It is an object of the invention to provide a method and apparatus for spectroscopically sampling bulk product that overcomes or ameliorates at least some of the aforementioned deficiencies and problems.